No matter what type of transaction that you think about, you will get the bill or receipt from it to prove that the transaction has been made and approved by the buyer and the seller. The same thing goes for dog bill of sale. If you have the business place that sell pets, then when somebody comes to your door and decide to buy a dog, you need to have the bill especially if what you have is special breed dog.
There are no certain rules about how a dog bill of sale must look like so you can made it on your own or if you want to be more practical, you can use free template for it. A bill must have some information inside of it that shows both parties have done the transaction willingly. What you can find on the bills are the dog price and the information about sides, the seller and the buyer where each of them must sign the bill.
Another important thing that you must include in your dog bill of sale is the information about the dog itself, such as how old he is, what breed he comes from, health record which lists his health history under your authority and vaccination that you have given to the dog, and for special dog, it may comes with certificate on it that you also must include it along with the bill. With the whole information you have, then the transaction can be closed up and you can hand over the dog to his new owner.